Server error i meet with PO list

I meet this issue?
Any help
Traceback (most recent call last):
File “/home/frappe/benches/bench-2017-01-10/apps/frappe/frappe/app.py”, line 55, in application
response = frappe.handler.handle()
File “/home/frappe/benches/bench-2017-01-10/apps/frappe/frappe/handler.py”, line 19, in handle
execute_cmd(cmd)
File “/home/frappe/benches/bench-2017-01-10/apps/frappe/frappe/handler.py”, line 40, in execute_cmd
ret = frappe.call(method, **frappe.form_dict)
File “/home/frappe/benches/bench-2017-01-10/apps/frappe/frappe/init.py”, lin

Please share full traceback.